The present disclosure relates generally to turbine engines and, more specifically, to systems and methods of cleaning turbine engines using a reagent composition that selectively dissolves constituents of foreign material therefrom.
Aircraft engines used to propel aircraft through certain routes often experience significant fouling due to heavy environmental particulate matter intake during flight, idling, take-off, and landing. Environmental fouling degrades performance in turbine components of such known aircraft engines. For example, one known mechanism for fouling is the increased roughness of turbine components caused by mineral dust ingestion. Specifically, this increased roughness results from the formation of micropits caused by particle impact. Subsequently, mineral dust particles accumulate in these pits and block cooling passages by forming layers of fouling material therein. High temperatures on surfaces in downstream stages of the turbine result in thermal alteration and solid-state mineral reactions of the accumulated mineral dust particles, which forms a calcia, magnesia, alumina, silica (CMAS) based reaction product. Consequently, water wash treatments, which are frequently used to clean the turbine components, often are not successful in removing the accumulated mineral dust and its secondary reaction products.
At least one known method of removing the accumulated mineral dust includes impinging dry ice particles against the turbine components. More specifically, the dry ice particles expand as they sublimate to facilitate cleaning the turbine components. However, dry ice is not specifically tailored to dissolve fouling deposits based on the elemental composition of the accumulated mineral dust and its reaction products, and instead focuses on mechanical removal of the foulant. Another known method includes treating surfaces of the turbine engine with an acid solution including HxAF6. Such known acid solutions are generally only tailored to remove low-temperature reaction-based products of mineral dust, and are generally only applied following engine tear-down in a service repair shop environment.